Add information text to output

[bolt12]

This PR fixes #1312

[edsko]

@TravisCardwell I've approved this PR and told @bolt12 to go ahead and merge this, but this tracerConfigWithoutASTReadError does feel a bit weird to me. It's only on the CLI, and only for this info command, so not a big deal, but nonetheless - do you have any thoughts on this?

[TravisCardwell]

I still do not understand why we are getting the error.

I did not think I got the error before, but I just checked with LLVM/Clang 14 and see it with that version as well. I likely just forgot about the error.

Does this error happen because the header is empty? I tried adding #define HS_BINDGEN_NOP_H to the header, but I still see the error.

Perhaps libclang is trying to parse the printed output? Surely not, but I do not know how to easily check this.

Suppressing the error (in this CLI command only) by changing the level to debug sounds like a suitable mitigation to me.

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BTW, when I first tried building with LLVM/Clang 14, it failed because of the cached build for LLVM/Clang 21 in the Cabal store:

Template Haskell error: [Warning] [HsBindgen] [builtin-include-dir] clang version mismatch:
  libclang version: clang version 21.1.6
  clang version:    clang version 14.0.6

This issue (#1244) is annoying, and it is frustrating that there is nothing we can do about it.

[bolt12]

From what I understood, Clang exits early without fully processing/parsing the input file, i.e. no AST is created and clang_parseTranslationUnit returns CXError_ASTReadError because no AST was built.

So in essence, it prints info and exits without completing the AST construction, regardless of file content

[TravisCardwell]

Looks good to me.